454 rebuild- 83 K3500

[ZacharyDouglas1992]

I have a build thread for this truck going, but I figured I would make a seperate one for simply the motor build as that will be usefull for a much broader audience. I know there is tons of them out there but one more can't hurt right? And mine will have to pass CA emissions in the end so if nothing else it may be a good starting point for others in the same boat.

The engine ran like new, so I was hessitant at first to touch it. But I pulled the motor out as I am doing a restoration on the truck, and the motor seemed to be leaking out of every seal possible. There were 4 places that the oil pan gasket was leaking, the front timing cover seal was so bad the spring was exposed, the rear intake gasket was leaking, and it leaked from the hoses on the sandwich style oil cooler adapter. Amazingly, the rear main seal didnt leak at all. Never the less I was losing a quart of oil every 400 miles or so and I knew I wasn't burning it. The motor has 83k original miles on it, and looks like someone did a (sloppy) re-ring job on it in the past. Which leaves me with a solid foundation but needing work. I had planned on just re-gasketing it to stop all the leaks, but after inspecting the guts I thought better of it and now am overhauling it. So here is the plan and where I am at so far.

Entire engine disassembled, down to the bare block.

The cylinders are in such good shape I am not going to touch them. They still have the cross hatching marks that new moly rings will love.

The crank will be getting turned. there is the slightest amount of wear from a little dirt getting in, and up to this point it was standard. However, the thrust bearing was about half as thick as it should be, and that is the main reason I am getting the crank worked on.


Anyhow, when it's all done I should have a long lasting, fun to drive motor that makes more torque than horsepower. And in a 10000 gvwr truck that's prrobably for the best. When I get home from work I will post all the parts/services and their prices. And the known specs of them. Any questions/suggestions/comments always welcome.

[Slammed84]

Im looking forward to this thread. I started a 496 build a couple years ago and then got married and procreated, so two years later its still on the backburner.
I have a mid eighties 4 bolt 454 truck block that was .060 over but all the bores were off a little so it will end up .070 over.
Heads are 781 oval ports and we put 2.19/1.88 valves in, will also do a light pocket port job before its done.
Bought a Scat stroker crank that works with the stock length rods, which are nice truck rods or "thumb rods".
Still was trying to figure out pistons, cause flat tops in a BBC are really low compression.
Definitely going with a hydraulic roller, and that was the bulk of what i am missing, parts wise.
Truck will be street driven, occasionally taken to the track.
Hoping for a solid 550 lb/ft, 500 hp

Good luck with your build, sounds like you know your stuff.
Take lots of good quality pics!

[ZacharyDouglas1992]

Thanks! Feel free to ask me anything you need since your build will be similar to mine, at least hyd roller big blocks if nothing else. Plus, chances are you'll ask me something and someone much more knowledgeable than I will have great answers. That's why I love this forum.

I am currently making a list of the parts I have, or will buy. Along with the machine work, etc. I'll post that tonight as I finish it.

As for your build,

sounds like a pretty good set of heads, if you aren't going to go with aluminum ones. I had the peanut ports on mine. By the time I would have picked up good bbc heads, and had the machine work done, it would have eclipsed the 800 I paid for new aluminum head, assembled. So I went that route.

I have heard mixed reviews on the cranks that use the stock length rods. Not from a performance aspect so much as that it can be a pain when it comes to clearance and balancing. but, you'll have more pistons to choose from, to look on the bright side.

To choose pistons for your application, summitracing has a fairly simple, but useful compression calculator. You will have to measure your deck clearance as it may be slightly different with the new crank. Mine was as follows, for an example.

My 454
Bore: 4.25
Stroke: 4.00
Cylinder Head Volume: 115cc
Dome Volume: -22 (22cc dome pistons)
Deck Clearance: .020
Compressed Gasket thickness: .039 (safe avg to use)
No. of cylinders: 8

That will give me about 9.7:1 compression, probably like 9.6 with valve reliefs.

your 496 (498 really haha)
Bore: 4.320
Stroke: 4.25
Cylinder Head Volume: ~118cc
Dome Volume: what you need to determine
Deck Clearance: you'll need to measure
Compressed Gasket thickness: .039 (safe avg to use)
No. of cylinders: 8

plug and play with available dome cc heads and find something around 9.5 you like. Keep in mind that If your heads have been shaved down at all you'll need to measure the chambers to get this to be accurate. I plugged in a 10cc dome piston and with your bore and stroke that was 9.36:1. That would be a great streetable CR with iron heads.

Since you have an 80's truck block, it will already be drilled for the cam retainer used for the Gen VI camshafts. Save yourself a world of headache and use one of those. This will help you avoid cam buttons and special timing covers and/or eating into your block with the cam gear. Summit sells the Gen VI timing set for like 60, comes with the retainer. It's only a single roller, but for a BBC that makes most of its power south of 5000 RPMs, should be plenty strong. its in the 502 crates after all. If you are dead set on a double roller, I think they have just the retainer available as well. Also, you'll need a melonized gear for the distributor. 40 bucks on summit. the part number will be on the list I post later on.

Good luck on your build! And congrats on the family.

[Slammed84]

Yeah Ive spent hours on that summit compression calculaItor. Truth is I got a smokin deal on those 781's, only paid $200 bare, and bought the valves. I am in pretty good with the machine shop so he didn't even charge me to cut the new valves.
But im pretty sure the heads have been milled so until i can cc them its just a guess. The machinist told me they were around 110cc but id like to confirm that myself.
Its for that reason I was having a little trouble choosing pistons cause flatties were around 8:1, and any kind of smaller dome puts me in the gotta run premium range. The only gas stations in tulsa that have real 100 % premium are smaller untrusted gas stations. Plus its only 91 octane.
I would be happy with 8.75:1 to 9.25:1, somewhere in between.
I think with a good quench area I should be okay with 100% 87 octane for the most part, I can always get sone octane booster I guess.

[ZacharyDouglas1992]

Well, if your heads are really 110cc, with true flat top pistons you'd be at right about 9 or so including the valve reliefs. So definitely get those measured, you may already be somewhere close to where you want to be, assuming your deck clearance is around .020 with the new crank and stock style pistons. unfortunately the .070 overbore makes for less options when it comes to pistons.

KB202-070 Here's one viable option. I'm sure you are already aware of these but when you plug in those figures at 110cc its like 9.03. Should even be friendly with 87 octane with careful timing and/or 180 or cooler thermostat.

[ZacharyDouglas1992]

here is the parts list...

Not taking into account the price of the core motor, or headers, or assuming you are building the one you've got, I have around 3k invested.

Costs could be easily cut down with hydraulic flat tappet cam, reworking iron heads, and for most of you that do not have to abide by ca smog laws you can find much more affordable headers.

But considering this will be a balanced, roller motor, I feel like 2800 isn't too severe an investment at all. An iron headed flat tappet cam long block goes for that, and you're still missing the goodies.

[Titomars]

I am going to follow this thread for ideas when it comes time to do some work on my 454. I don't plan to touch the bottom end at this time the engine runs strong as is and only has 100k on the odometer.

[ZacharyDouglas1992]

In too deep now...

Well actually I was as of about 3 weeks ago. Haha

[andrewmp6]

Plus if you hide aftermarket parts most think its stock and won't think about stealing your truck.

[Slammed84]

Yeah when I get my 496 (498) done im gonna find a 396 badge for my air cleaner and when I smoke other trucks I can say " its just a little 396".
Thats the best part about strokers and boring and stuff. No one ever knows for sure unless you tell them

[ZacharyDouglas1992]

Yep. I can honestly say you can make some of the least flashy horsepower with a BBC. Not too many other motors out there can surpass 500+ horses while still looking relatively stock.

[suxtobu65]

What heads are those?

[ZacharyDouglas1992]

No idea on the brand. A small shop here where I am from carries them, it was 750 cash for the pair + tax assembled. They sell them on ebay, shipped, for 899. I think I have the ebay item number in the pdf I attached. I'm sure they come from overseas but from whom exactly I couldn't tell you. It's hard to beat the price though.

[ZacharyDouglas1992]

Some more parts finally came in. Off to the machine shop to be balanced! Thanks to a bad starter when I got the truck, and a sloppy mechanic using standard threaded bolts in a fine threaded balancer, I needed new ones. And I figured 9.6:1 compression sounded better than 7.9:1, sooo new pistons. Two of mine cracked removing the rods, so that was all the excuse I needed to buy new ones!

[ZacharyDouglas1992]

wooo

[y5mgisi]

Subscribed! Should be a good motor!

[Got Smoke?]

Subscribed.... thinking of rebuilding the 454 in my 88 to go into my 79.

[Slammed84]

Sorry if you already stated it but what type of cam and specs will be run? Any idea of compression ratio?

[Slammed84]

nevermind, just saw the spreadsheet.
Im no expert.... but I'm thinkin you could run a bit bigger cam and still make considerable torque. let those new aluminum heads breathe and do their job!

[Slammed84]

BBC's also really benefit from more exhaust lift and duration. If it were me I would go for the biggest cam you could run without needing a stall convertor.
Look for dual pattern with at least 8 to 10 degrees more exhaust duration and .010 more exhaust lift.
Something like .530/.540 with 230/236 degrees advertised duration

[ZacharyDouglas1992]

let me just start of by saying that you're right on all accounts. I could've gone more aggressive on the cam, and it would definitely benefit from exhaust lift/duration.

But, I have to adhere to pretty strict California smog laws, which means I had to take it easy on the cam, and I can't really mess with the timing at all which also would help with a more aggressive cam.

The springs in the heads can take much more lift, and for anyone else using this build For ideas, from the fun states without the nazi air resource board, definitely use a more aggressive cam and really open things up!

The reality of it for me, is that I have a towing vehicle with 4.56 gears, and the low end is where it really matters. It'll idle nice, last a long time, and tow my toys just fine. If I'm ever feeling like I'm lacking in top end, I'll just hop in my Chevelle and satisfy that need haha.

Thanks always for all the comments/suggestions/advice. That's what makes these threads useful to those seeking some advice.

And speaking of this thread. I checked on my rotating assembly yesterday. Should be done by the end of next week. Having my rods machined to use floaters instead of pressed for the Pistons. So that added a little time. But I'll be glad I did it, If nothing else when I have it apart next time, and I don't have all the Pistons ruined removing them.

[ZacharyDouglas1992]

Some progress finally! in the midst of moving I haven't had nearly the amount of time I would like to for this truck. But I'll never have "enough" time haha.

[ZacharyDouglas1992]

life is full of surprises and work has forced me to move 4 times since I tore this truck down. that being said, ive had time on weekends here and there to make slight progress. Here's the engine now. All but ready to drop in.

[ZacharyDouglas1992]

I have the 454 dropped into the truck now, and am starting to accomplish all the tedious tasks that go along with it. I've reinstalled the oil cooler sandwich adapter, new cooler lines, power steering pump, hydroboost lines, new water pump, new alternator, new smog pump and pulley, new idlers, tensioner, etc . That brings me to what I am about to ask...

Does anyone here have a thorough Vacuum line diagram for an 83 GMC K3500? I have the remnants of what is on my air cleaner but I don't think it addresses everything. Getting this thing to smog is going to be a PITA.